Press brakes are used to shape sheet material, typically sheet metal or the like, into a desired shape. Press brakes commonly include a lower table and an upper table, with one of the tables being vertically movable toward the other table. Most commonly, the lower table is movable while the upper table is stationary. Forming tools are mounted to each of these tables so that when the tables are brought toward one another, a workpiece positioned between the forming tables is bent into the desired shape.
It is common for the upper table to include a male forming tool having a bottom, downwardly oriented workpiece-deforming surface of a desired shape, such as a right angled bend. The bottom table will typically carry a die having an upper, upwardly oriented workpiece-deforming surface of an appropriate shape which is aligned with the male forming die. When the die is brought together with the forming tool, a workpiece positioned between the two is pressed by the forming tool into the die and thus is given an appropriate bent shape. The forming tools and dies commonly are horizontally elongated so that workpieces of various widths can be accommodated.
It is often necessary to exchange forming tools and dies when a different bending operation is to be performed. The dies commonly rest in a die holder attached to the bottom table of the press brake. The forming tools usually are carried by tool holders mounted to the upper table of the press brake. It is important to ensure that the dies are precisely aligned with the forming tools to ensure that the respective workpiece-deforming surface of these parts are precisely aligned with one another.
A number of attempts have been made to enable vertical, as opposed to horizontal, adjustment of the die with respect to the lower table. For example, U.S. Pat. No. 4,736,612 (issued to Russell, the teachings of which are incorporated herein by reference) suggests an arrangement utilizing a die holder which rests on a plurality of independently adjustable wedges moveable laterally within a fixed channel. By sliding the wedges from one side to the other beneath the die holder, the die holder can be moved upwardly or downwardly within the channel.
Similarly, U.S. Pat. No 4,586,361 (issued to Reinhorn et al., the teachings of which are also incorporated herein by reference) suggests the use of a specialized wedge to adjust the height of the die mounting tool with respect to the press brake. In particular, Reinhorn et al. propose a wedge which incorporates a specialized rod 57. By adjusting the length of the rod 57, the shape of the wedge is changed, altering the curvature of the wedge along its length.
While the systems of Russell and Reinhorn et al. provide some degree of vertical adjustment, they do not enable an operator to move the die laterally with respect to the table of the press brake. Such a fixed lateral position is acceptable if the precise position of the workpiece-deforming surface of the forming tool does not vary at all from one forming tool to the next. As a practical matter, though, there does tend to be some minor variation in the relative positions of the workpiece-deforming surfaces of the forming tool and the die.